OUTLINE Modules 10 11 12 13 SENSATION 1 Sensation vs Perception 2 Psychophysics 3 Vision 4 Audition NOTE Read about Touch Taste Smell Balance PERCEPTION 2 Organization and Interpretation Some Perceptual Illusions Gestalt Psychology Constancy in Perception Perceptual Set Depth Perception Perceptual Adaptation Extra Sensory Perception Experiencing events 2 Stages Converting the physical world into a mental representation transduction And relaying that information to the brain Variations of light experience of color Variations of are pressure experience of Stage 1 SENSATION The processes of conduction EX Transduction sound Stage 2 PERCEPTION the processes of selection organization and interpretation EX we can recognize the color GREEN we can distinguish BACH from BRITNEY SPEARS PSYCHOPHYSICS What is it The study of relationships between physical characteristics of stimuli energy and our psychological experience of them EX Light brightness Sound volume Pressure weight Taste sweetness Key concepts Absolute Thresholds smallest magnitude of a stimulus that can be reliably discriminated from NO stimulus at least 50 of the time Difference Threshold minimum difference between two stimuli that a person can detect at least 50 of the time just noticeable differences EX detecting salt in your pasta adjusting the sound on your iPod to the best and comfortable volume PSYCHOPHYSICS Signal Detection Theory predicts how and when we detect the presence of a stimulus amidst background stimulation complex decision mechanisms are involved to determine if a stimulus exists Based on both 1 stimulus strength 2 our experiences Point Absolute thresholds and Just noticeable differences are not fixed o Our sensitivity to a stimulus varies based on experiences Factors that affect Absolute and Difference Thresholds 1 Chance variation noise in the system influence sensitivity 2 Stimulus intensity Weber s Law the greater the intensity of a stimulus the larger the difference must be to detect a difference They must differ by a constant proportion 3 Sensory Adaptation our sensitivity to an unchanging stimulus diminishes EX getting into a hot tub When you get into a hot tub it s really hot that you can t even get in Once you ve been in the hot tub it doesn t feel as hot anymore VISION Q How do we turn light energy physical stimulus into vision psychological experience 2 aspects of light energy light waves are crucial Wavelength The distance between peaks of the light wave Corresponds to our sensation of color R O Y G B I V Short wavelength violets and blues Long wavelength reds and oranges Amplitude The intensity of the light wave Corresponds to our sensation of brightness Small amplitude dull colors Large amplitude bright colors Structure of the EYE read text 1 Rods cells in the periphery of the retina sensitive of light 2 Cones cells in the center of the retina Forvea sensitive to focus and color perception VISION Two Major Theories of Color Vision 1 Trichromatic theory Young Hemholtz Creation of colors any color can be created by combining the red green and blue light in varying combinations In our eyes we have 3 kinds of cones Cone 1 maximally sensitive to blue Cone 2 maximally sensitive to green Cone 3 maximally sensitive to red Experience of colors results from mixing different levels of response from these 3 cone types Note Additive light vs subtractive paint color mixing Colorblindness VISION Two Major Theories of Color Vision 2 Opponent process theory opposing retinal processes enable color vision neural impulses are antagonistic a stimulus that elicits a response from the red depresses a response of green ON Red vs OFF Green Blue vs Yellow White vs Black Explains Color After Images EX American Flag The brain knows that the world does not spontaneously change color When you stare at the white dot in the center of the flag once you look at a white page you see the actual color of the American flag AUDITION HEARING Q How do we turn variations in air pressure physical stimulus into our sense of hearing psychological experience Two aspects are crucial 1 Frequency The number of complete cycles per unit time Hertz cycle per second Corresponds to our psychological sensation of pitch 2 Amplitude volume The intensity of the wave Corresponds to our psychological sensation of Structure of the Ear read text AUDITION HEARING Perceiving Pitch Volume Location Perceiving Pitch highs vs low sounds 1 Place theory Difference pitches produce responses on different places on the basilar membrane Works well with high pitched sounds 2 Frequency theory Different pitches causes the basilar membrane itself to vibrate at different frequencies Works well with low pitched sounds Perceiving volume loud vs soft sounds No movement of the basilar membrane but number of stimulated hair in the cell Perceiving Location where is that sound coming from Why do we have 2 ears Left vs Right Up vs Down Front vs Behind What s up with your own voice PERCEPTION What is it Def The process by which we select organize and interpret these mental representations EX We can recognize the color red We can distinguish Bach from Britney Spears Perception ORGANIZATION INTERPRETATION Most Important Point of the day There is NOT a 1 1 correspondence between our perceptual representation of the world and the physical reality of the world Why Because physical information is ambiguous Ex seeing your roommate across the pond We know she did not shrink to a smaller size we understand that things farther away are seen as being small We do this with all sorts of physical world information We take the available information and interpret it based on what we know about our world PERCEPTION Perceptual Illusions What is an illusion Case where the rules that we used to interpret the world which we are usually true are not true and lead us to mis interpretation Examples of Visual Illusions 1 Vertical vs Horizontal lines o The vertical line seems longer than the horizontal line but in reality they are the same length 2 Context effects o If the sentence is hard to make out we can ultimately understand what the message is o Information in the real world can be ambiguous but our brain can interpret it 3 Experience effects the world Muller Lyer Why so many visual illusions Visual capture vision dominates RULES GESTALT PSYCHOLOGY Gestalt psychology tried to specify the rules of perception for how we distinguish coherent separate objects German word for form or whole We work hard to
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